Sensor cartridge, sensor feeder, and measuring instrument

ABSTRACT

A sensor cartridge ( 1 ) for use on a sensor feeder includes a cartridge body ( 10 ) and a mold ( 12 ). The cartridge body ( 10 ) has an upper surface ( 10   a ), a front ( 10   c ) extending continuously from the upper surface, and a plurality of sensor-holding slots ( 11 ). Each of the sensor-holding slots ( 11 ) includes a first opening formed in the upper surface ( 10   a ) and a second opening formed in the front ( 10   c ) and communicating with the first opening. The mold ( 12 ) closes the first opening and second openings in case sensors are charged in the sensor-holding slots ( 11 ).

This application is a Division of U.S. Pat. No. 7,470,400, which has afiling date of Aug. 20, 2002, and which is a U.S. National Stage ofPCT/JP01/01325, filed on 22 Feb. 2001.

TECHNICAL FIELD

The present invention relates to a sensor cartridge for accommodating asensor for measuring the concentration of a particular substancecontained in body fluid, such as glucose contained in blood. The presentinvention also relates to a sensor feeder used for taking out a sensorfrom such a sensor cartridge, and to a measuring instrument providedwith such a sensor cartridge.

BACKGROUND ART

For diabetes treatment, the concentration of glucose contained in bloodof a patient (hereinafter referred to as “blood glucose level.”) need bemaintained in a normal range, and the management of the blood glucoselevel by the patient himself or herself is an important treatment.Particularly, for the treatment of insulin-dependent diabetes, thepatient needs to inject insulin by himself or herself to maintain theblood glucose level in a normal range, so that the measurement of theblood glucose level is essential for the patient.

Portable blood glucose level measuring instruments which can be used bythe patient himself or herself is already commercially available, anexample of which is disclosed in JP-A-4-357452. Generally, a bloodglucose level measuring instrument comprises an instrument body, and adisposable sensor (test piece) for use as mounted to the main body. Thesensor is provided with an enzyme electrode including an electrodeportion and a reacting portion contacting the electrode portion. When apredetermined portion of the sensor is brought into contact with bloodas an analyte, part of the blood is introduced into the reacting portionby capillary action, causing an enzyme reaction or an electrochemicalreaction. As a result, an anode current is generated at the electrodeportion contacting the reacting portion. The anode current is convertedto a blood glucose level at an arithmetic circuit provided in the mainbody and the computation result is displayed at the display portion.

When such a sensor having an enzyme electrode, or a so-called biosensoris exposed to the air for a long period of time, the reagent containedin the reacting portion is deteriorated due to its absorption of waterin the air. In such a case, accurate measurement results cannot beobtained. Therefore, this kind of sensor is supplied to the patient in ahermetically sealed state by wrapping the sensor with aluminum laminatedfilm for example. In this case, for measuring the blood glucose level,the patient needs to first break the laminated film by hand and thentake out the sensor from the laminated film wrappings for mounting tothe measuring instrument. These steps need be performed properly withouttouching the enzyme electrode portion or the analyte contacting portion,which gives psychological stress to the patient. This is rather seriousfor children, the elderly, adults who recognize not to be clever withtheir hands, or visually-defected patients. Since this kind of measuringinstrument is usually designed to perform proper measurement with assmall amount of analyte as possible, there is a tendency to reduce thesize of a sensor. Accordingly, the proper handling of a sensor becomesincreasingly difficult for the patient.

As a manner of hermetically sealing the sensors, a plurality of sensorsmay be collectively sealed in a can provided with a lid for example,instead of individually wrapping each sensor with a laminated film asdescribed above. According to this arrangement, for measuring the bloodsugar level, the patient needs to open the lid of the can to take outone sensor for mounting to the measuring instrument. This causes aproblem that all the sensors in the can are exposed to the air everytime the lid is opened. Further, this arrangement does not considerablyfacilitate the handling of the sensors as compared with the manner ofwrapping the sensors with laminate films. Thus, the handling of thesensors become difficult as the sensors become smaller in size.

JP-A-6-308115 discloses another manner of hermetically sealing thesensors, which utilizes a cartridge. The cartridge includes a pluralityof chambers arranged in a row, each of which accommodates a sensor.Specifically, each chamber of the cartridge has a cylindricalconfiguration which is open at opposite ends thereof. The sensorcartridge is mounted to a predetermined sensor feeder provided with aprotecting bar. By inserting the projecting bar into each of thechambers through one end toward the other end thereof, the sensor ispushed out from the chamber through the other end.

With this arrangement, the handling of the sensors is easier than in theabove-described arrangements, because the user, or the patient need notmanually peel off the sealing member at each chamber of the sensorcartridge. However, it still has the following problems.

Firstly, since the sensor pushed by the projecting bar needs to breakthrough the sealing member sealing the end of the chamber, the materialsfor the sensors are limited to certain kinds in view of the rigidity.This may hinder the size reduction and thickness reduction of thesensors.

Secondly, the manufacturing of the sensor cartridge is troublesome,because it is required to insert sensors in respective chambers and toseparately seal opposite ends of each chamber with a sealing member.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to eliminate or lessen theproblems described above. Specifically, an object of the presentinvention is to provide a sensor cartridge which enables taking-out ofthe hermetically-sealed sensors by a simple operation and which can bemanufactured easily. Another object of the present invention is toprovide a sensor feeder provided with such a sensor cartridge, and ameasuring instrument provided with such a sensor cartridge.

According to a first aspect of the present invention, there is provideda sensor cartridge used as attached to a main body of a sensor feeder.The cartridge includes a cartridge body and a sealing member. Thecartridge body includes an upper surface, a front surface connectedthereto, and a plurality of sensor retaining grooves. Each of the sensorretaining grooves includes a first opening formed at the upper surfaceand a second opening formed at the front surface for communication withthe first opening. The sealing member closes the first opening and thesecond opening with a sensor loaded in the sensor retaining groove.

Preferably, the sensor retaining groove includes a sensor accommodatingportion for accommodating the sensor, and a pusher receiving portion forreceiving a pusher contained in the main body of the sensor feeder. Thesensor accommodating portion communicates with the first opening and thesecond opening. The pusher receiving portion communicates with the firstopening while being connected to the sensor receiving portion at alocation opposite to the second opening.

Preferably, the sensor retaining groove includes a sensor accommodatingportion for accommodating the sensor, and a cutter receiving portion forreceiving a cutter contained in the main body of the sensor feeder. Thesensor accommodating portion and the cutter receiving portioncommunicate with the first opening and the second opening while beingconnected to each other.

Preferably, the cutter receiving portion is deeper than the sensoraccommodating portion in a thickness direction of the sensor cartridge.

Preferably, the front surface is connected to the upper surface via arounded portion.

Preferably, the cartridge further includes a rear surface opposing thefront surface, and the rear surface is formed with feed grooves forengaging a pin contained in the main body of the sensor feeder and foradvancing the sensor cartridge by a predetermined pitch in response toone reciprocal movement of the pin.

Preferably, each of the feed grooves includes a first groove portionextending thicknesswise of the sensor cartridge and a second grooveportion extending between an intermediate portion of the first grooveportion and an upper end of an adjacent first groove portion.

Preferably, the intermediate portion of the first groove portion isprovided with a projection for guiding the pin moving upward within thefirst groove portion toward the second groove portion.

Preferably, the second groove portion is provided with a projection forpreventing the pin from entering the second groove portion from theupper end of the first groove portion.

Preferably, the plurality of sensor retaining grooves are arranged atthe predetermined pitch.

According to a second aspect of the present invention, there is provideda sensor feeder comprising a sensor cartridge and a pusher. The sensorcartridge includes a cartridge body and a sealing member foraccommodating a plurality of sensors. The pusher is movable verticallyand back and forth for pushing one of the plurality of sensors. Thecartridge body includes an upper surface, a front surface connectedthereto, and a plurality of sensor retaining grooves. Each of the sensorretaining grooves includes a first opening formed at the upper surfaceand a second opening formed at the front surface for communication withthe first opening. The sealing member closes the first opening and thesecond opening with a sensor loaded in the sensor retaining groove. Thesensor retaining groove includes a sensor accommodating portion foraccommodating the sensor, and a pusher receiving portion for receivingthe pusher. The sensor accommodating portion communicates with the firstopening and the second opening, and the pusher receiving portioncommunicates with the first opening white being connected to the sensorreceiving portion at a location opposing the second opening.

Preferably, the feeder further includes a cutter for breaking thesealing member. The sensor retaining groove includes d cutter receivingportion for receiving the cutter. The cutter receiving portioncommunicates with the first opening and the second opening while beingconnected to the sensor accommodating portion.

Preferably, the feeder further includes a pin, and the cartridge bodyincludes a rear surface opposite to the front surface. The rear surfaceis formed with feed grooves for engaging the pin and for advancing thesensor cartridge by a predetermined pitch in response to one reciprocalmovement of the pin.

Preferably, the feeder further includes an operation member which ismovable vertically and back and forth. The pusher, the cutter and thepin are movable vertically in response to the vertical movement of theoperation member. The pusher is movable back and forth in response tothe back-and-forth movement of the operation member.

Preferably, the feeder further includes a spring for biasing theoperation member upward.

According to a third aspect of the present invention, there is provideda measuring instrument. The measuring instrument comprises a pluralityof sensors each of which includes an analyte applying portion, areacting portion, and a base end provided with a sensor terminal, asensor cartridge including a cartridge body and a sealing member foraccommodating the plurality of sensors, a pusher movable vertically andback and forth for pushing one of the plurality of sensors, and anarithmetic circuit including a circuit terminal for performingcomputation based on a current generated at the reacting portion. Thecartridge body includes an upper surface, a front surface connectedthereto, and a plurality of sensor retaining grooves. Each of the sensorretaining grooves includes a first opening formed at the upper surfaceand a second opening formed at the front surface for communication withthe first opening. The sealing member closes the first opening and thesecond opening with the sensor loaded in the sensor retaining groove.The sensor retaining groove includes a sensor accommodating portion foraccommodating the sensor, and a pusher receiving portion for receivingthe pusher. The sensor accommodating portion communicates with the firstopening and the second opening. The pusher receiving portioncommunicates with the first opening while being connected to the sensorreceiving portion at a location opposite the second opening. The sensoris accommodated in the sensor accommodating portion so that the analyteapplying portion faces the second opening. The circuit terminal is soprovided as to contact the sensor terminal of the sensor when theanalyte applying portion is pushed by the pusher for exposure to theoutside of the instrument.

Preferably, the instrument further includes a cutter for breaking thesealing member, and the sensor retaining groove includes a cutterreceiving portion for receiving the cutter. The cutter receiving portioncommunicates with the first opening and the second opening while beingconnected to the sensor accommodating portion.

Preferably, the instrument further includes a pin, and the cartridgebody includes a rear surface opposing the front surface. The rearsurface is formed with feed grooves for engaging the pin and foradvancing the sensor cartridge by a predetermined pitch in response toone reciprocal movement of the pin.

Preferably, the instrument further includes an operation member which ismovable vertically and back and forth, and a movable member which ismovable vertically together with the operation member. The pin isprovided at the movable member.

According to a fourth aspect of the present invention, there is provideda sensor cartridge. The sensor cartridge comprises a cartridge bodyhaving an upper surface and a plurality of sensor retaining grooves eachhaving an opening formed at the upper surface, and a sealing member forclosing the opening. Each of the sensor retaining grooves includes asensor accommodating portion for accommodating the sensor, and a cutterreceiving portion for receiving a cutter for breaking the sealingmember. The sensor accommodating portion and the cutter receivingportion communicate with the opening while being connected to eachother.

Other features and advantages of the present invention will becomeclearer from the detailed description given below with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating an example of sensor cartridgeaccording to the present invention.

FIG. 2 is a plan view of the sensor cartridge shown in FIG. 1.

FIG. 3 is a rear view of the sensor cartridge shown in FIG. 1.

FIG. 3 a is a view showing undulations of a feed groove along pointsA-B-C-A′ in FIG. 3.

FIG. 4 is a sectional view taken along lines IV-IV in FIG. 1.

FIG. 5 is a perspective view showing an example of sensor foraccommodation in a sensor cartridge of the present invention.

FIG. 6 is an exploded perspective view of the sensor shown in FIG. 5.

FIG. 7 is a perspective view showing an example of sensor feederaccording to the present invention.

FIG. 8 is a side view of the sensor feeder shown in FIG. 7.

FIG. 9 is a sectional view taken along lines IX-IX of FIG. 8, showingthe operation member held at the restored level.

FIG. 10 is a sectional view taken along lines X-X of FIG. 9, showing theoperation member held at the restored level.

FIG. 11 is a sectional view taken along lines X-X in FIG. 9, showing theoperation member at the retreated position on the pushed level.

FIG. 12 is a sectional view taken along lines X-X in FIG. 9, showing theoperation member at the advanced position on the pushed level.

FIG. 13 is a perspective view showing an example of measuring instrumentaccording to the present invention.

FIG. 14 is an enlarged sectional view illustrating the portions aroundthe sensor eject hole of the measuring instrument of FIG. 13.

FIG. 15 is a sectional view taken along lines XV-XV in FIG. 14.

MODE FOR CARRYING, OUT THE INVENTION

Preferred embodiments of the present invention will be described belowwith reference to the accompanying drawings.

FIGS. 1-4 illustrates an example of sensor cartridge according to afirst aspect of the present invention. The sensor cartridge includes acartridge body 10 and a sealing member 12.

The cartridge body 10 is molded from a moisture-impermeable resin suchas high-density polyethylene to have a general contour of an elongateparallelepiped. Specifically, the contour of the cartridge body 10 isdefined by an upper surface 10 a, a bottom surface 10 b, a front surface10 c, a rear surface 10 d and end surfaces 10 e, 10 f. The upper surface10 a, the front surface 10 c and the end surface 10 e are generallyparallel to the bottom surface 10 b, the rear surface 10 d and the endsurface 10 f, respectively. The upper surface 10 a is connected to thefront surface 10 c via a rounded portion 10 g. Hereinafter, thedirection extending from the upper surface 10 a toward the bottomsurface 10 b is defined as the thickness direction of the sensorcartridge 1 or the cartridge body 10. Similarly, the direction extendingfrom the front surface 10 c toward the rear surface 10 d is defined asthe widthwise direction, whereas the direction extending from the endsurface 10 e toward the end surface 10 f is defined as the longitudinaldirection of the sensor cartridge 1 or the cartridge body 10.

The cartridge body 10 is formed with a plurality of sensor retaininggrooves 11 which are arranged at a predetermined pitch L longitudinallyof the sensor cartridge and extend widthwise. Each of the sensorretaining grooves 11 is open at the upper surface 10 a, the roundedportion 10 g and the front surface 10 c. As shown in FIGS. 1 and 2, eachsensor retaining groove 11 comprises a sensor accommodating portion 11 afor directly accommodating a sensor 2, a cutter receiving portion 11 band a pusher receiving portion 11 c for respectively receiving a cutterand a pusher included in a sensor feeder. The dimension of the sensoraccommodating portion 11 a is determined correspondingly to that of thesensor 2 to be received therein. The cutter receiving portion 11 b islocated adjacent to the sensor accommodating portion 11 a forcommunication therewith and is open, together with the sensoraccommodating portion 11 a, at the upper surface 10 a, the roundedportion 10 g and the front surface 10 c of the cartridge body 10. Thecutter receiving portion 11 b is deeper than the sensor accommodatingportion 11 a in the thickness direction. The pusher receiving portion 11c, which is open at the upper surface 10 a, is arranged adjacent to andin communication with an end of the sensor accommodating portion 11 aextending widthwise. The pusher receiving portion 11 c is substantiallyequal in width to the sensor accommodating portion 11 a but shallowerthan the sensor accommodating portion 11 a in the thickness direction.

As shown in FIG. 4, a sensor 2 in the form of a short sheet strip isloaded in each of the sensor retaining grooves 11. The sheet-likesealing member 12 is provided to continuously extend over the uppersurface 10 a, the rounded portion 10 g and the front surface 10 c of thecartridge body 10 to collectively close the openings of all the sensorretaining grooves 11. Thus, each of the sensor retaining grooves 11 ishermetically sealed. For the sheet-like sealing member 12, use may bemade of aluminum foil or a laminated member formed by laminating a resinfilm on an aluminum foil.

As shown in FIG. 3, the rear surface 10 d of the cartridge body 10 isformed with feed grooves 13. The feed grooves 13 receive a pin-likedriver which is included in the sensor feeder to be described later andwhich is movable reciprocally thicknesswise of the sensor cartridge 1,thereby providing a cartridge feed mechanism in the sensor feedertogether with the pin-like driver. Each of the feed grooves 13 includesa first groove portion 13 a extending thicknesswise of the sensorcartridge 1 and a second groove portion 13 b extending between anintermediate portion of the first groove portion 13 a and the upper endof an adjacent first groove portion 13 a. The first groove portions 13 aare arranged at a predetermined pitch L longitudinally of the sensorcartridge 1. Each feed groove 13 is formed, at the bottom thereof, withprojections 13 c, 13 d so that the pin-like driver, which is movablereciprocally in the sensor feeder thicknesswise of the sensor cartridge1, properly moves within the feed grooves 13 along the path indicated bythe arrow P.

FIG. 3 a illustrates undulations along the pin transfer path in the feedgrooves 13. The points A, B, C, A′ in FIG. 3 a correspond to the pointsA, B, C, A′ at the surfaces of the feed grooves 13 shown in FIG. 3. Whenthe pin-like driver indicated by broken lines in FIG. 3 a moves upwardfrom the point A within the first groove portion 13 a, the pin-likedriver comes into contact with the projection 13 c adjacent to the pointB and is guided into the second groove portion 13 b. Then, the pin-likedriver moves over the projection 13 d at the bottom surface of thesecond groove portion 13 b to reach the point C, which generallycorresponds to the upper end of the next first groove portion 13 a. Themovement of the pin-like driver which has reached the point C isrestricted by the projection 13 d so as not to move back along thesecond groove portion 13 b. The pin-like driver then moves downward fromthe point C to pass over the projection 13 c to reach the point A′.

In this way, during a single reciprocal movement of the pin-like driverthicknesswise of the sensor cartridge 1, the pin-like driver of thesensor feeder moves from one first groove portion 13 a to be received inthe adjacent first groove portion 13 a. Since the first groove portions13 a are arranged at the predetermined pitch L, the reciprocal movementof the pin-like driver advances the sensor cartridge 1 stepwise at thepitch L longitudinally thereof relative to the pin-like driver or themain body of the sensor feeder.

The sensor cartridge 1 having the above-described structure has thefollowing advantages. Since each of the sensor retaining grooves 11 isopen at the upper surface 10 a of the cartridge body 10, a sensor can beeasily inserted therein from above. Further, since both the upperopening and the front opening of each sensor retaining groove 11 aresealed by the sheet-like sealing member, the interior of the sensorretaining groove can be easily maintained in a hermetically sealedstate. Moreover, since the upper surface 10 a and the front surface 10 cof the cartridge body 10, to which the sealing member is to be attached,are connected to each other via the rounded portion 10 g of thecartridge body 10, all the sensor retaining grooves 11 can be sealed bya single sheet of sealing member by a single, relatively easy processstep. Therefore, the sensor cartridge 1 can be made by a manufacturingprocess which is relatively easy in terms of the loading of sensors andthe sealing with a sealing member, which enhances the manufacturingefficiency.

FIGS. 5 and 6 illustrate an example of biosensor 2 to be accommodated inthe above-described sensor cartridge 1. The biosensor 2, which is in theform of a short sheet strip having a rounded tip end, includes aninsulating base 20, a spacer plate 21 laminated on the base 20, and acover plate 23 further laminated on the spacer plate 21. The insulatingbase 20 is formed with an operative electrode pattern 24 and acounterpart electrode pattern 25.

The operative electrode pattern 24 is made up of a rectangular operativeelectrode 24 a provided adjacent the tip end of the insulating base 20,a terminal 24 b provided adjacent the base end of the insulating base20, and a lead 24 c connecting these to each other. The counterpartelectrode pattern 25 is made up of a counterpart electrode 25 asurrounding the operative electrode 24 a adjacent the tip end of theinsulating base 20, a terminal 25 b provided adjacent the base end ofthe insulating base 20, and a lead 25 c connecting these to each other.

The spacer plate 21, which has a tip end configured identically to thatof the insulating base 20, is shorter than the insulating base 20.Therefore, in the state where the spacer plate 21 is laminated on theinsulating base 20, the terminals 24 b, 25 b provided adjacent the baseend of the insulating base 20 are exposed to the outside. The spacerplate 21 is formed with a slit 21 a open at the tip end of the sensor.The spacer 21 is laminated on the insulating base 20 so that theoperative electrode 24 a and the counterpart electrode 25 a are exposedat the slit 21 a. The portions formed with the operative electrode 24 aand the counterpart electrode 25 a are provided with a non-illustratedreagent layer, or a reacting portion.

The cover plate 23, which has a rounded tip end similarly to theinsulating base 20, is formed with a through-hole 23 a whichcommunicates with the base end of the slit 21 a of the spacer plate 21.Thus, a body fluid path 22 is defined by the slit 21 a of the spacerplate 21, and the cover plate 23 and the insulating base 20 sandwichingthe spacer plate 21 from above and below. The body fluid path 22 is openat one end adjacent the tip end of the sensor while also being open atthe other end via the through-hole 23 a formed in the cover plate 23.

In the case where the sensor 2 is used for measuring the blood glucoselevel, the reacting portion contains a reagent such as glucose oxidasewhich is an oxidization enzyme, and potassium ferricyanide as amediator. When the biosensor is loaded in a measuring instrument, theterminals 24 b, 25 b are electrically connected to the counterpartterminals of the instrument to be ready for measurement. When body fluidas an analyte is applied to the tip end of the sensor 2, the body fluidis introduced into the body fluid path 22 by capillary action. In thebody fluid path, enzyme reaction and electrochemical reaction occur atthe reacting portion which is made up of the operative electrode 24 a,the counterpart electrode 25 a and the reagent layer covering theseelectrode, thereby generating anode current at the operative electrode.It is to be noted that the sensor 2 is not limited to theabove-described biosensor in the form of a short sheet strip, and usemay be made of any other sensor as long as it includes an analyteapplying portion and terminals while having a configuration suitable forinsertion into a measuring instrument.

FIGS. 7-12 illustrate a sensor feeder 3 according to a second aspect ofthe present invention. As shown in FIG. 7, the sensor feeder 3 includesa cartridge mount portion 30, a grip portion 31 extending from thecartridge mount portion 30, and an operation member 34 supported by thecartridge mount portion 30. In this feeder, the side provided with thecartridge mount portion 30 is regarded as the front, whereas the sideprovided with the grip portion 31 is regarded as the rear.

The cartridge mount portion 30 is in the form of an upwardly-open boxdefined by a front wall 31 a, a side wall 31 b, an opposite side wall 31c, a vertical partition wall 31 d adjoining the grip portion 31 and abottom wall 31 e. The cartridge mount portion 30 is formed with a sensorcartridge insertion hole 32 penetrating through the side walls 31 b, 31c. The front wall 31 a is formed with a sensor eject hole 33.

The operation member 34 is movable vertically and back and forthrelative to the cartridge mount portion 30. Specifically, as shown inFIGS. 8-12, the cartridge mount portion 30 is upwardly provided with anupwardly-open accommodation recess defined by the front wall 31 a, theside walls 31 b, 31 c and a horizontal partition wall 31 f. Theoperation member 34 is accommodated and retained in the accommodationrecess. The operation member 34 has a width corresponding to thedistance between the side walls 31 b and 31 c and has an upper surfaceformed with a plurality of non-slip projections 35. The operation member34 is formed, at the sides thereof, with a guide projection 36. Theguide projection 36 is slidable along a respective one of L-shaped guidegrooves 37 formed on the inner surfaces of the side walls 31 b and 31 c.Each L-shaped guide groove 37 includes a vertically extending firstportion 37 a, and a second portion 37 b extending horizontally from thelower end of the first portion. Thus, the operation member 34 is movablevertically along the first portion 37 a of the guide groove 37 between arestored level and a pushed level. Further, at the pushed level, theoperation member is movable horizontally along the second portion 37 bbetween a retreated position and an advanced position. Herein, therestored level means the state where the guide projection 36 is locatedat the upper end of the first portion 37 a of the guide groove 37,whereas the pushed level means the state where the guide projection 36is located at the lower end of the first portion 37 a or at any positionwithin the second portion 37 b. The retreated position means the statewhere the guide projection 36 is located at the connecting point betweenthe first portion 37 a and the second portion 37 b, whereas the advancedposition means the state where the guide projection 36 is located at thefront end of the second portion 37 b.

The operation member 34 has a lower surface which is integrally formedwith a stay 39 extending downward through a horizontally-extending slit38 formed at the horizontal partition wall 31 f. The stay 39 has a lowerend on which is integrally supported a plate-like pusher 40 capable ofentering the pusher receiving portion 11 c of each sensor retaininggroove 11. Thus, the pusher 40 is movable back and forth correspondinglyto the back-and-forth movement of the operation member 34. The operationmember 34 is movable vertically along the first portion 37 a of theguide groove 37 only at the retreated position. The stay 39 and thepusher 40 are so arranged that the pusher properly enters the pusherreceiving portion 11 c provided on the rear side of the sensor retaininggroove 11 of the sensor cartridge 1 when the operation member 34 movesvertically at the retreated position.

The cartridge mount portion 30 incorporates, under the horizontalpartition wall 31 f, a movable member 41 which is movable verticallycorrespondingly to the vertical movement of the operation member 34. Themovable member 41 includes a horizontal plate portion 41 a and a rearskirt portion 41 c extending downward from a rear portion of thehorizontal plate portion 41 a. Similarly to the horizontal partitionwall 31 f, the horizontal plate portion 41 a is formed with a slit 42for allowing the passage of the pusher 40 integrally provided under theoperation member 34 for back-and-forth movement. The horizontal plateportion 41 a of the movable member 41 is provided, at the lower surfacethereof, with a cutter 43 extending downward. The cutter 43 is in theform of a plate capable of entering the cutter receiving portion 11 b ofthe sensor retaining groove 11 of the sensor cartridge 1. The pin-likedriver 44 for engagement with the feed grooves 24 formed at the rearsurface 10 d of the sensor cartridge 1 is provided at the skirt portion41 c of the movable member 41 to project forwardly. The skirt portion 41c provided with the driver 44 is elastically deformable to some extentunder an external force. Therefore, when the pin-like driver 44 movesover the projections 13 c, 13 d of the feed grooves 13 as described withreference to FIG. 4, the skirt portion 41 c elastically retreats.

As clearly shown in FIG. 9, a pair of upwardly-extending support bars 45are integrally formed on the upper surface of the horizontal plateportion 41 a of the movable member 41. Each support bar 45 penetratesthrough a guide hole 31 fg formed in the horizontal partition wall 31 ffor engagement with the reverse surface of the operation member 34. Thereverse surface of the operation member 34 is formed with guide grooves34 a each capable of sliding while receiving the upper end of thesupport bar 45.

As clearly shown in FIG. 10, a pair of leaf springs 46 are provided aselastically deformed, each of which has one end fixed to the verticalpartition wall 31 d with the other end engaging the lower surface of thehorizontal plate portion 41 a of the movable member 41. Thus, themovable member 41 is normally biased upwardly in the apparatus.Therefore, as long as the guide projection 36 engages the first portion37 a of each L-shaped guide groove 37, the operation member 34 is pushedby the movable member 41 for elastically restoring upward. A downwardpush of the operation member 34 from the restored level to the pushedlevel causes corresponding downward movement of the movable member 41,the cutter 43 integrally formed thereon, and the driver 44. At thistime, the pin-like driver 44 moves downward along the first grooveportion 13 a of the feed groove 13 to move over the projection 13 cprovided at the intermediate portion of the first groove portion. Whenthe pushing force applied to the operation member 34 is relieved, theoperation member 34 and the movable member 41 move upward to therestored level by the elastic restoring force of the paired leaf springs46. At this time, the pin-like driver 44, initially moving upward alongthe first groove portion 13 a, is guided from the first groove portion13 a to the second groove portion 13 b by the projection 13 d and thenmoves over the projection 13 d to be received in the adjacent firstgroove portion 13 a.

With the sensor feeder described above, a sensor can be taken out from asensor cartridge as follows.

First, a sensor cartridge 1 is inserted into the cartridge insertionhole 32 of the cartridge mount portion 30 of a sensor feeder 3 from oneside thereof. By pushing the operation member 34 plural times, a feedmechanism, which is provided by the engagement of the feed grooves 13formed on the rear surface 10 d of the cartridge body 10 with thepin-like driver 44 movable vertically together with the movable member41, operates to advance the cartridge 1 in a predetermined direction bythe number of steps corresponding to the number of pushes.

As shown in FIG. 11, to take out the sensor 2 accommodated in the sensorretaining groove 11 of the sensor cartridge 1, the user pushes down theoperation member 34, which is biased upward by the paired leaf springs46, while holding the grip portion 31. At this time, the guideprojection 36 at the side surface of the operation member 34 slidesalong the vertically-extending first portion 37 a of each guide groove37. Subsequently, as shown in FIG. 12, the operation member 34 is slidtoward the front of the apparatus. At this time, the guide projection 36slides along the horizontally-extending second portion 37 b of the guidegroove 37. As long as the guide projection 36 is located in the secondportion 37 b of the guide groove 37, the operation member 34 cannotreturn to the restored position, thereby keeping the pushed state.

As shown in FIG. 11, when the operation member 34 is depressed, thecutter 43 moves correspondingly to enter the cutter receiving portion 11b of the sensor retaining groove 11 of the sensor cartridge 1. At thistime, the cutter 43 breaks the sheet-like sealing member 12 sealing theupper opening and the front opening of the sensor retaining groove 11.At the same time, the push on the operation member 34 cause the pusher40 on the operation member 34 to break the sealing member 12 for entryinto the pusher receiving portion 11 c of the sensor retaining groove11. The pusher receiving portion 11 c is located adjacent to and held incommunication with the sensor accommodating portion 11 a on the rearside of the cartridge. Therefore, when the operation member 34 is slidforward as shown in FIG. 12, the pusher 40 moves from the pusherreceiving portion 11 c to enter the sensor accommodating portion 11 a topush the sensor 2 forward. As a result, part of the sensor 2 passesthrough the front opening of the sensor retaining groove 11 to projectout through the sensor eject hole 33 of the front wall 31 a facing theopening. In the case where the sensor 2 is loaded in the sensorretaining groove 11 with terminals 24 b, 25 b located on the front sideof the apparatus, the above-described operation makes the terminals 24b, 25 b of the sensor 2 project outward through the sensor eject hole33. In this state, the user inserts the portion provided with theterminals 24 b, 25 b of the sensor 2 into a predetermined portion of ameasuring instrument, thereby performing intended measurement such asthe blood glucose level measurement without directly touching the sensor2 with fingers.

When the operation member 34 is returned from the advanced position tothe retreated position, the operation member 34 returns from the pushedlevel to the restored level due to the biasing force of the paired leafsprings 46. At this time, as described with reference to FIG. 4, thesensor cartridge 1 advances in the predetermined direction by the pitchL by the feed mechanism consisting of the feed grooves 13 and thepin-like driver 44. In this embodiment, the sensor retaining grooves 11are also arranged at the pitch L. Therefore, when the sensor cartridge 1is advanced in the predetermined direction by the pitch L, anothersensor retaining groove 11 which is still sealed by the sealing member12 comes directly under the cutter 4 provided at the operation member34. Thus, the feeder is ready for taking out the next sensor 2.

In this way, with the sensor feeder 3 having the above-describedstructure, a user, or a patient can take out a sensor 2 properly fromeach sensor retaining groove of the sensor cartridge 1 and mount thesensor to a measuring instrument by a simple operation without directlytouching the sensor. At this time, since only a relatively smallmechanical load is exerted on the sensor 2, the sensor itself is notrequired to have a considerably large rigidity. Therefore, noinconvenience is caused even if a sensor is further reduced in size asrequired.

FIGS. 13 through 15 illustrate a measuring instrument 5 according to athird aspect of the present invention.

The measuring instrument 5 includes a main body 50 for the measuringinstrument 5, and a sensor feeder 3 which is the second aspect of thepresent invention described above. The main body 50 is provided at thegrip portion of the sensor feeder 3. The main body 50 has an obversesurface provided with a display 51 such as an LCD. The display 51indicates the results of measurement performed using a sensor.

The sensor feeder 3 built in the measuring instrument 5 has a structurewhich is similar to that described above with reference to FIGS. 7-12,but further has structural features described below. As shown in FIG.14, in the measuring instrument 5, each sensor 2 is loaded in the sensorcartridge 1 so that the terminals 24 b, 25 b are positioned on the rearside of the instrument.

As clearly shown in FIGS. 14 and 15, the measuring instrument includesterminals 52 provided in the sensor eject hole 33 at the front wall 31 aof the cartridge mount portion 30 for electrical contact with theterminals 24 b, 25 b of the sensor 2 when the sensor projects out fromthe cartridge 1. The spacer plate 21 and the cover plate 23 may be maderelatively short for ensuring contact between the terminals 24 b, 25 bof the sensor 2 and the terminals 52 of the instrument.

Since the other portions of the sensor feeder 3 are structurally similarto those described before, the detailed description thereof is omitted.

For measuring body fluid, the sensor 2 in the sensor cartridge 1 ispushed forward by pushing down the operation member 34 and sliding itforward. At this time, the tip end of the sensor 2 projects through thesensor eject hole 33 at the front wall 31 a of the instrument as shownin FIG. 13, whereas the terminals 24 b, 25 b at the base end of thesensor 2 are brought into electric contract with the terminals 52 on theinstrument side as shown in FIG. 15.

The user or the patient brings blood, which is drawn out onto the skinusing e.g. a lancet, into contact with the analyte applying portion atthe tip end of the sensor 2. Part of the blood is introduced into thebody fluid path of the sensor 2 by capillary action. In the sensor, thereaction reagent dissolves in blood to cause enzyme reaction andelectrochemical reaction, thereby generating an anode current at theoperative electrode. The anode current passes through the terminals 52on the side of the measuring instrument into a circuit in the measuringinstrument 5. The measurement results such as the blood sugar leveldetermined using a predetermined calibration curve is displayed at thedisplay 51.

When the measurement finishes, the sensor 2 is pulled out for disposaland the operation member 34 is returned to the restored level. At thistime, the sensor cartridge 1 is advanced stepwise by the feed mechanismto be ready for the next measurement.

In this way, with the measuring instrument 5 according to the thirdembodiment of the present invention, intended body fluid measurement canbe performed without touching the sensor.

The present invention is not limited to the above-described embodiments.The configuration of the sensor retaining grooves may be modifiedappropriately in accordance with the given sensors. Further, the feedgrooves provided at the rear surface of the sensor cartridge body may beconfigured otherwise as long as they can advance the cartridge step bystep correspondingly to the vertical movement of the pin-like driver ofthe movable member.

1. A measuring instrument comprising: a plurality of sensors each ofwhich includes an analyte applying portion, a reacting portion, and abase end provided with a sensor terminal; a sensor cartridge including acartridge body and a sealing member for accommodating the plurality ofsensors; a pusher movable vertically and back and forth for pushing oneof the plurality of sensors; and an arithmetic circuit including acircuit terminal for performing computation based on a current generatedat the reacting portion; the cartridge body including an upper surface,a front surface connected thereto, and a plurality of sensor retaininggrooves, each of the sensor retaining grooves including a first openingformed at the upper surface and a second opening formed at the frontsurface for communication with the first opening, the sealing memberclosing the first opening and the second opening with the sensor loadedin the sensor retaining groove; the sensor retaining groove including asensor accommodating portion for accommodating the sensor, and a pusherreceiving portion for receiving the pusher, the sensor accommodatingportion communicating with the first opening and the second opening, thepusher receiving portion communicating with the first opening whilebeing connected to the sensor receiving portion at a location oppositeto the second opening; the sensor being accommodated in the sensoraccommodating portion so that the analyte applying portion faces thesecond opening; the circuit terminal being so provided as to contact thesensor terminal of the sensor when the analyte applying portion ispushed by the pusher for exposure to the outside of the instrument. 2.The measuring instrument according to claim 1, further comprising acutter for breaking the sealing member, the sensor retaining grooveincluding a cutter receiving portion for receiving the cutter, thecutter receiving portion communicating with the first opening and thesecond opening while being connected to the sensor accommodatingportion.
 3. The measuring instrument according to claim 1, furthercomprising a pin, the cartridge body including a rear surface oppositeto the front surface, the rear surface being formed with feed groovesfor engaging the pin and for advancing the sensor cartridge by apredetermined pitch in response to one reciprocal movement of the pin.4. The measuring instrument according to claim 3, further comprising anoperation member which is movable vertically and back and forth, and amovable member which is movable vertically together with the operationmember, the pin being provided at the movable member.